"The difference between animals and robots is robots get stuck while animals squirm their way through," said inventor-engineer Joseph Ayers of Boston's Northeastern University.

His robo-lobsters, designed to roam the sea floor and find undersea mines, are equipped with "neurons" that allow them to work their way around clutter much as real lobsters would.

Also on display were a combination submersible Jet Ski, a virtual air hockey game, and corporate entries such as General Motors' hydrogen-powered vehicles and General Electric's technologies to generate energy and make drinking water out of sea water.

Another robot that resembles a small tank on its hind legs was admired by Maj. Jeff Stone, who was taking a break from the Army's own exhibit nearby.

"Our soldiers love these things," Stone said, referring to iRobot's Packbot, a hundred of which are in Iraq defusing and exploding bombs. U.S. soldiers assigned to operate the $100,000 robots have even given them affectionate names.

"Drop some C-4 (plastic explosive) right on the weapon, and you don't have to worry about it" hurting anyone, Stone said.

Packbot manufacturer iRobot also promoted its automated vacuum-cleaner line at NextFest. At $329, the costliest versions can be programmed to do their work while the homeowner is away.